Aging of the population due to increased life expectancy has brought with it a major increase in cognitive disorders associated with normal cerebral aging and with pathological cerebral aging occurring in the course of neurodegenerative diseases such as, for example, Alzheimer's disease.
The majority of substances used today in treating cognitive disorders associated with aging act by facilitating the central cholinergic systems--either directly, as in the case of acetylcholinesterase inhibitors (tacrine, donepezil) and cholinergic agonists (nefiracetam), or indirectly, as in the case of nootropic agents (piracetam, pramiracetam) and cerebral vasodilators (vinpocetine).
Besides their cognitive properties, substances acting directly on the central cholinergic systems often have antalgic properties but also have hypothermic properties, which can be undesirable.
It has been therefore been especially valuable to synthesise new compounds that are capable of opposing the cognitive disorders associated with aging and/or of improving cognitive processes and that can possess antalgic properties without having hypothermic activity.